Lexus 1UZ 4.0l V8 with MJLJ and COP's

[cribbj]

Hello everyone, first post here. I've purchased a MJLJ for my project, and hope to be up & running in a few weeks.

We recently finished building this motor with new forged pistons, mild head porting, and new valves, and in its final trim it'll be supercharged and injected, running from the AEM EMS currently running the 2JZ-GTE motor in my Supra, and which will be replaced by this V8.

For the breakin of this motor, I wanted to keep things as simple as possible, so I decided to put a carb on it, and a standalone ignition. I built an adapter plate for the Holley and bolted it on, and had heard good things about the EDIS8 and the MJLJ, so I had a 36-1 trigger wheel made up in place of the standard Lexus 12 tooth wheel, and here's the results.

This engine originally comes with twin distributors driven from the cam gears, but it also comes with a 12 tooth crank trigger wheel, and #1 TDC cam triggers on both intake cams, so it's a doddle to convert to full crank triggered ignition.

I've fitted it with Supra COP's, which are wearing Camry extender boots. The COP's are connected in parallel for a waste spark setup, and when I chucked up my 36-1 wheel in a drill, and tested the EDIS8 for spark, it seemed happy with the configuration. Had a nice little blue/red spark, which didn't look quite as strong as I'd hoped, but perhaps that was because of my dodgy test configuration. FYI, the Supra COP's measured about 0.9 ohms each from my Fluke, so the EDIS8 is looking at about 0.45 ohms on each output.

We'll see how it goes in a few weeks when I get this puppy on the engine dyno for the breakin. Sorry for the longwinded post!

[DannyP]

I know I am not talking from experience yet, as my system is not up and running yet. But I am pretty sure the EDIS needs to see a square wave, i.e. peaks(teeth) and valleys of the trigger wheel need to be the same length. This might or might not be a problem, I am sure the experienced guys will chime in.................

[cribbj]

Thanks for that comment; I had hoped to see more symmetry in the peaks and valleys also, so it'll be interesting to see how it works. That's the primary reason I was determined to "run" the system from my electric drill; that and to make sure I didn't have a duff EDIS module. If anyone else has taken photos of their spark at the plug, I'd be very interested in seeing it.

[Hiperformance71]

Hi,

The EDIS work with a VR sensor, this type of sensor gives a sinusoidal wave, not a square wave like Hall effect sensors. You can check in the forum, on it is present all the documentation about the EDIS working principle.

The possible reason for the poor spark is possible to be the COP configuration, this because the EDIS have to supply the signal to 2 coils and not 1, with 2 coil the amount of current flowing trought the EDIS circuitry is bigger and can make the EDIS work in overheat or break in a short time, check this item. Check the +12v to the coils, in some cases, the alimentation isn't soo good. The other thing is, have a good 12v positive?? consider the car, when is running, the batt measures 13.5 to 14.5 V and is well known the effect of the bat tension in the performances of all the electrical components like ECUs, fuel pumps, injectors and obviusly, coils. Check this.

From the photo, the spark don't looks too bad for me!

cheers,



sorry for my bad english!

[cribbj]

The possible reason for the poor spark is possible to be the COP configuration, this because the EDIS have to supply the signal to 2 coils and not 1, with 2 coil the amount of current flowing trought the EDIS circuitry is bigger and can make the EDIS work in overheat or break in a short time, check this item. Check the +12v to the coils, in some cases, the alimentation isn't soo good. The other thing is, have a good 12v positive?? consider the car, when is running, the batt measures 13.5 to 14.5 V and is well known the effect of the bat tension in the performances of all the electrical components like ECUs, fuel pumps, injectors and obviusly, coils. Check this.

From the photo, the spark don't looks too bad for me!

cheers,

sorry for my bad english!

When I initially wired the EDIS, I was considering putting the coils in series to reduce the current demand, however in searching the 'net a bit, it seemed that the high end ECU people like Autronic, MoTeC and others, favored wiring the coils in parallel, so that's what I did. During my little test, I monitored the EDIS module to see if it was overheating, and it didn't even get warm to the touch.

I wonder if anyone else has used the software "stimulator" for the EDIS and monitored their spark?

[cribbj]

I had crossposted about this apparent weak spark in this thread: http://www.autosportlabs.org/viewtopic.php?t=1415 and after a couple of exchanges with Oliver, the light finally went on, and I realised, as Hiperformance71 had already suggested, that the EDIS couldn't drive both coils in parallel, and was probably current limiting the circuit to only 1/2 the amperage needed by the coils.

I was then in contact with a knowledgeable guy over on the MS forums who was already familiar with the problem and has recommended connecting (2) EDIS8's in a quasi-parallel arrangement to sort this weak spark problem.

So the VR input signal would go to both EDIS's, the SAW would go to both, however the PIP would only be connected from one.

Then each output from an EDIS would go to a single coil. So although they're not exactly wired in parallel (except for the VR and SAW), they'd be operating in parallel, and each coil could then get full charging current.

So, the 2nd EDIS is on order, and I'll have it ready to install, should the engine fall on its face on the dyno.

[DannyP]

I am very interested in this setup for a dual plug 911 rs motor I have in the works! I can't wait to see how this works for you, then I'll get my hands on a couple of EDIS 6 models.

[cribbj]

Hi Danny, we're on the dyno now, but have been chasing other problems, namely a timing belt that keeps wanting to jump teeth. Strange problem, considering the whole front of the motor is brand new, but we have new parts arriving today so I'll put a complete new timing system on it and try again. I'm currently going to try to run with the single EDIS and the 8 coils, as after we had a couple of backfires (due to the mistiming) at least I know they're igniting!

But I do have another EDIS standing by, as well as a set of Ford coilpacks and HT leads, so I have two alternatives to try if the single EDIS and 8 COP's don't work.

Here's a pic of my 36-1 trigger wheel, showing (I hope) the correct orientation with the VR sensor, although the sensor itself was missing from this pic......doh. This was a really clean install on the Toyota as this wheel pops on in the place of the OEM 12 tooth wheel. In this pic the motor is at #1 TDC, and as you can see, the 5th tooth "after" the missing tooth is centered where the VR sensor "should" be. I edited this photo with MS Paint, because the original photo was taken before I ground off the "missing" tooth. Sure was easier removing the tooth in the photo than it was with the grinder!


Here's the way I have the 8 coils wired now (firing order is 18436572 - same as Chevy):



And the way I'll wire them with the 2nd EDIS8:



And finally, here's the motor on the dyno (SuperFlow 901):

[cribbj]

After a number of Murphy related glitches, we got the motor running on the dyno.

It would not run with just the single EDIS8 and the 8 Supra COP's, so to get it running initially, I pulled off the COP's and rewired the ignition with Ford EDIS coilpacks, and it fired right up. Made a few pulls and it ran fine.

Then I wanted to try the COP's again, so I rewired everything and put a 2nd EDIS8 in parallel with the first, according to the diagram I previously posted, and it fired up and ran fine - every bit as well as with the EDIS coilpacks. We only ran it to 5000 RPM because I was concerned about fuel/air distribution with this carb on a supercharger manifold, so we couldn't check or confirm the rumors about the EDIS being RPM limited.

Here's a link to the motor running with the twin EDIS8's and the 8 COP's:



Next step is to put the supercharger and fuel injection on and run it in anger.

[dr.occa]

sounds nice cribbj...nice to see a fellow Houstonian in these parts.

[Hiperformance71]

Hello Cribbs!

Nice work!! is looks good and promises a lot i think! well done! Good look for the final tuning sessions!! let us know the results!!!

Chears,

[cribbj]

Thanks Dr. Occa and HiPerf

To save time, I'm going to let the dyno owner & operator finish the mechanical parts of putting the supercharger & fuel system on while I'm at work overseas next month. Then I'll rewire it for the EMS when I get back, and hopefully we'll do the next dyno session in late December or early January.

We intend to run it again initially under boost with the twin EDIS8's & COP's, then hopefully will have an experimental ignition mux/demux, driven from the AEM, ready for trial and we'll have a go with that.

I'll update the thread when there's something new.

John

[dr.occa]

cribbj i read earlier in this thread how you were having problems with weak spark using a single edis unit for 8 COPs. i'd like to run 4 COPs for my setup: should i expect to run into the same problem?

[cribbj]

Dr. Occa, are you asking about driving 4 COP's from an EDIS8 or an EDIS4? In other words are you still trying to drive pairs of COP's as I was? Are you running an 8 cylinder motor or a 4 cylinder?

I've "heard" of someone running pairs of BMW COP's, but wired in series (mine were in parallel), and he said it worked, but it may limit the spark at high RPM.

I would think that pairs of COP's with integral ignitors could be run (triggered) from an EDIS unit. This would be an interesting experiment.

[dr.occa]

Dr. Occa, are you asking about driving 4 COP's from an EDIS8 or an EDIS4? In other words are you still trying to drive pairs of COP's as I was? Are you running an 8 cylinder motor or a 4 cylinder?

I've "heard" of someone running pairs of BMW COP's, but wired in series (mine were in parallel), and he said it worked, but it may limit the spark at high RPM.

I would think that pairs of COP's with integral ignitors could be run (triggered) from an EDIS unit. This would be an interesting experiment.

thx for a speedy reply.

we read the same write up in regards to the bmw COPs setup cribbj!

i borrowed your diagram and altered it for an EDIS 4 application (my application) and applied the in-series configuration. i have another EDIS4 module i could always hook up in parallel but am hoping the single EDIS will suffice. i also wasn't sure about the secondary grnds on the COPs so i did not address them in the attached diagram. any insight would be greatly appreciated.